X-ray mammography is a key research area for improvement in breast cancer detection through screening programs. Primary digital acquisition appears to have theoretical advantages for generation of high quality images compared to film-screen receptors, including potentially superior latitude and dose efficiency. However, technological considerations of currently available CCD technology limit the maximum area that this type of system can practically image to less than that required for general screening purposes. Also, these sensors suffer from significant image quality problems due to the light conversion process in the X-ray converter. A concept for digital X-ray mammography was demonstrated in the Phase I research that has the potential to overcome the limitations of conventional imaging systems. Prototype sensors were fabricated that demonstrated sensitivity at least equivalent to film-screen systems for standard mammography X-ray sources, with superior resolution and dynamic range. This system was shown to have the potential to greatly exceed the capabilities of currently available systems. A compact system may be fabricated into standard screening size formats with dramatically improved image quality to serve as replacements for mammography cassettes. We shall complete the development of the new mammography X-ray sensor during Phase II, and use it with actual pre-clinical samples to quantitatively compare results to existing systems. For the first time his technology will allow X-ray mammography image quality to be determined by the underlying digital sensor. PROPOSED COMMERCIAL APPLICATION: The market for mammography screening equipment is in the billions of dollars. A low-cost, large-area format X-ray imager with significantly higher image quality than current systems provide will find widespread acceptance in many medical and industrial settings.